1. Field of the Invention
The present invention relates to a decorative sheet used for interior materials of construction materials such as furniture and fittings.
2. Disclosure of the Related Art
There has been a proposal on a decorative sheets for various use mentioned above which is prepared by laminating an ink layer and a surface protective layer curable with active energy ray sequentially on a paper base material. In order to obtain decorative paper having resistances to solvents, contamination and chemicals, the thickness of the surface protective layer provided on outermost surface is usually increased. However, when the thickness of the surface protective layer is increased, a coated product of the surface protective layer is severely warped by the hardening shrinkage, giving rise to the problem that it is difficult to handle the coated product and breakdown of the base material is readily caused during coating. As a method solving this problem, there is a proposal that a curing agent is added to an ink layer to cure the ink layer in the publication of Japanese Patent Application No.2003-090149. In this case, however, there is the problem that production efficiency is decreased because the adjustment of the amount of the curing agent is complicated when the color of the ink layer is adjusted, and also the problem that the adhesion of the cured ink layer to the surface protective layer that is curable with active energy ray is deteriorated.
A decorative sheet is required to have a resistance to peeling off by cellophane tape, that is, the property which is resistant to peeling of the surface of the decorative sheet when the applied cellophane tape is peeled off from the decorative sheet. To satisfy this requirement, Japanese Patent Application Laid-Open No. 4-117466 discloses that silicone acrylate is added in a composition of the surface protective layer to control the composition having a viscosity less than a fixed value. The silicone acrylate is thereby made to move easily to the surface, thereby imparting good resistance to cellophane tape peeling.
However, in the case of controlling the mobility of the silicone acrylate by changing the viscosity of the composition, there are problems that the ratio of the mobility varies according to the coating speed, and the amount of an oligomer used to improve the material properties of the composition is limited. Because, the addition of a matting agent sometimes increases the viscosity of the composition when the gloss of the surface protective layer is adjusted, the amount of the matting agent to be added is limited. Accordingly, there is a problem that it is difficult to control the viscosity and glossiness of the composition.